CyCloNe!

Hey guys after I did my belts and waterpump I noticed my vac readings are low around 11-12hg on cold start and 16-17hg warmed up. I checked the balance shaft and it appears they line up correctly. I have all new vac lines and before the belts my vac was 16hg on cold and around 20-21hg warm. Any ideas?

I see some minor cracking in my throttle body pipe connector and in my connector from the turbo to the intercooler pipe and I wonder if these are my suspects.

Thanks for your assistance!

mytrplseven

I would expect that anything in the intake system after the throttle body that is cracked or suspect probably is defective and therefore leaking. I don't know about turbo intakes but the NA intake boot is 2" and using a pvc cap with an air fitting screwed in and applying 7 to 10 psi, and spraying all vacuum lines, throttle body and fittings on the intake with soapy water solution quickly and cheaply shows them with lots of bubbles. I had two on my NA: one at the temperature probe under the intake runner and the other was the shaft seals on the throttle body.

CyCloNe!

Ya, I'll try that method... I have new vac lines all around, new lindsey silicone j-boot (which I am selling soon- have a maf now), new maf, new idle air control valve, new intercooler to boost pipe connectors. So all that is left is the throttle body seals and the two large hoses mention before.

So I'll try the soapy method and see what I find

Kerry Chadderton

Yeah, awesome test!

Where is this air temperature probe of which you speak? I have the intake off and in the process of changing all lines. I don't see no stinking probe! You have me worried. Am I missing something.

Paulyy

the vacuum will change with a maf

dirtyTurbo

I've got some pretty serious cracks at the same spot(new one is on the way) as well as a sweet boost leak and my vacuum is 15lbs cold and 20-21 warmed up. Are you saying the maf is on your car now? Also how does it idle/run?

CyCloNe!

I had the maf on all summer and my readings where 16hg cold. Since I change belts and it did get colder my vac has been lower. If the balance belt is too tight will it effect the vac readings?

mytrplseven

I can't say for certain all 944's have a temp sensor under the last two intake runners but my '87 NA does. One of the vacuum lines that runs from the base of the throttle body goes to it and since it's hotter in there than anywhere else in the engine compartment, the little 90 rubber boot fitting ages real fast. I got another one and installed it with a touch of liquid rubber sealant just to be secure. No more bubbles from there.